Method for transmission of alarm messages to subscriber terminals in radio communications system

ABSTRACT

Alarm messages are transmitted to subscriber terminals of a radio communication system by signalling the alarm presence through a control channel to the subscriber terminals by at least one base station of the radiocommunication system using at least one system information item. Upon reception of the system information item by the subscriber terminals, the subscriber terminals transmit at least one respective recorded alarm signal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and hereby claims priority to GermanApplication No. 10 2005 050 416.7 filed on Oct. 19, 2005, the contentsof which are hereby incorporated by reference.

BACKGROUND

Described below is a method for emission of alarm messages to subscriberterminals in a radio communications system, in particular for emissionto mobile subscriber terminals in a mobile radio system. Also describedare a subscriber terminal, a radio network controller and a radiocommunications system for carrying out the method.

The occurrence of catastrophes, caused either naturally or by people,still represents a major requirement for the public authorities inparticular with regard to the need to provide a rapid and comprehensivealarm system for the population affected. The traditional use of alarmsirens which are installed covering areas in at least some countries inthis case in particular has the disadvantage that no specificinformation can be transmitted, not least because it cannot be assumedthat the population wish to distinguish between different alarms.Further known methods for alarming the population include television andradio broadcast transmissions, although these have the disadvantage thatthey can be received only by terminals that are being used.

In addition to this use of public facilities, methods have beendeveloped which provide alarms by cable-based or mobile communicationssystems. In particular, mobile radio systems appear to be suitable forapplications such as these in this case, since, in particular incountries with a high penetration rate, a large proportion of thepopulation can be accessed irrespective of their current location.Methods based on communications systems have the disadvantage, however,that the dedicated dialling of a large number of telephones takes a longtime. This is particularly true when using the so-called short messageservice (SMS), as is implemented inter alia in the known GSM mobileradio system. Furthermore, the transmission of short messages has thenegative effect that the mobile radio system, which is generally alreadyheavily loaded, is additionally loaded, thus making it possible forfurther delays to occur in the transmission of short messages.

Methods are therefore being introduced to speed up the transmission ofshort messages, making use of the so-called “cell broadcasting”functionality of the GSM mobile radio system. In this context, referenceis made by way of example to the internet page that was available atwww.cell-alert.co.uk/emergency_management.htm, which also supported theabove statements. Despite the advantages achieved in this way, it is,however, disadvantageously necessary in terms of the alarm speed and theload on the mobile radio system for each of the subscribers to haveenabled the function of reception of cell broadcast messages on theirterminals, since the terminal will otherwise not receive such messages,or display them.

SUMMARY

An aspect is therefore to specify a method which ensures certainreception and emission of alarm messages on subscriber terminals.

According to the method described below, the presence of an alarm issignalled to the subscriber terminals by at least one system informationitem from at least one base station in a radio communications systemusing a control channel, and at least one respectively stored alarmmessage is transmitted as a consequence of this by the subscriberterminals.

Inter alia, the features of the method described below advantageouslymake it possible to inform subscriber terminals of the existence of analarm by system information, irrespective of their current status, thatis to say irrespective of whether they are in a so-called idle mode orin an active speech or payload data transmission mode, thus achievingfar greater coverage. In addition, each subscriber terminal canindividually control the output of an alarm message. For example, theoutput may be in the form of speech selected by the subscriber.

Another advantage over the use of the cell broadcast functionalitydescribed in the introduction is that there is no relationship betweenthe reception of the system information transmitted using a controlchannel and the presence of a subscription for a service such as this,or connection of this service. In fact, every subscriber terminal isable to receive and to appropriately evaluate system information. Inaddition, the method advantageously does not require any interactionwhatsoever by the subscriber.

The method advantageously avoids interference with services which areactive at the time when the alarm is transmitted. For example, thesubscriber terminal can output an alarm message without having tointerrupt an active speech or data call, so that the subscriber can thencontinue the call and end it normally, or else ends the existing callwhile the alarm is being output.

Subscriber terminals which do not support changes or the addition ofsystem information are not disadvantageously affected by the methodsince they ignore additional information blocks.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages will become more apparent andmore readily appreciated from the following description of exemplaryembodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a block diagram of a radio communications system based on theUMTS Standard,

FIGS. 2 a and 2 b are a frame structure diagrams for two examples oftransmission of alarm messages in system information blocks, and

FIG. 3 is a flowchart for the method described below.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments,examples of which are illustrated in the accompanying drawings, whereinlike reference numerals refer to like elements throughout.

By way of example, FIG. 1 shows a simplified structure of a radiocommunications system based on the known UMTS Standard, in which themethod can be implemented in the same way in radio communicationssystems to other Standards, for example, GSM or future generations.

The structure of a radio communications system to the UMTS Standardincludes one or more mobile switching centers MSC which are based onso-called circuit-switched connections, as well as management of variousfunctionalities of the system. The mobile switching center MSCfurthermore carries out the function of acting as the interface to thepublic telephone network PSTN (Public Switched Telephone Network). Inaddition to mobile switching centers MSC, so-called gateways GW alsoexist, for example SGSN and GGSN, which allow an interface betweenpacket-switched connections in networks with packet-orientedtransmission PDN (Packet Data Networks), for example the Internet, withthe transmission based on the Internet Protocol IP.

A multiplicity of radio network controllers (RNC are connected to themobile switching center MSC and/or to the gateway GW, in which, interalia, physical resources of the radio interface are managed. A radionetwork control RNC is in turn connected to a multiplicity of basestations NB1, NB2 (Node B) which can set up and initiate connections toterminals UE (User Equivalent) using assigned physical resources of theradio interface. Every base station NB1, NB2 in each case uses theallocated physical resources to supply at least one geographic region,which is also referred to as a radio cell Z1, Z2. The transmission onthe radio interface takes place both in the uplink direction UL and inthe downlink direction DL. Both the base stations NB1, NB2 and theterminals UE each have transmitting/receiving devices SEE for signaltransmission on the radio interface. Furthermore, the radio networkcontroller also has a transmitting/receiving device SEE forinterchanging data and signalling messages with the base stations andthe mobile switching center and/or the gateway. The terminal UE and theradio network controller RNC furthermore each have a control device STby which the method can be carried out, as will be described in thefollowing text.

In mobile radio systems based on the GSM and UMTS Standards, systeminformation which is transmitted on so-called broadcast channels, forexample the so-called BCCH or BCH (Broadcast Common Control Channel orBroadcast Control Channel, respectively) is transmitted by basestations, is received by subscriber terminals in the so-called idlemode, and is evaluated. In this context, reference should be made to thetechnical specification in 3GPP TS 25.331, Rel. 6.4.0 (2004-12),Technical Specification Group Radio Access Network, Radio ResourceControl (RRC) protocol specification. However, when subscriber terminalsare in the so-called connected mode, that is to say they are activelymaking a call for speech or packet data transmission, system informationcan also be transmitted via so-called dedicated control channels. Inthis context, reference should be made to the technical specificationsin 3GPP TS 44.018, Rel. 7.1.0 (2005-09), Technical Specification GroupGSM/EDGE Radio Access Network, Radio Resource Control (RRC) protocol and3GPP TS 44.060, Rel. 7.1.0 (2005-09), Technical Specification GroupGSM/EDGE Radio Access Network, General Packet Radio Service (GPRS),Mobile Station (MS)—Base Station System (BSS) interface, Radio LinkControl/Medium Access Control (RLC/MAC) protocol. This distinction willbe taken into account in the following text, in which an implementationof the method using a UMTS-based system will be described first of all,followed by an implementation using the GSM-based system.

As shown in Table 8.1.1 in 3GPP TS 44.018, Rel. 7.1.0, systeminformation in a UMTS-based system may have different geographictransmission ranges, referred to as the “area scope”. For example, adistinction is drawn on the basis of transmission in the coverage areaof the entire network (PLMN—Public Land Mobile Network) or only in oneradio cell (Cell).

The structure of system information is generally highly flexible sinceit is of modular construction and can therefore be extended in a simplemanner. System information can therefore have signalling for an alarm oran alarm message added to it in order to implement the method. Anaddition such as this is not critical for the so-called RRC (RadioResource Control) protocol. For example, the system information hasalready been added in the past, in order to provide location services.In addition, system information which is being changed by additions forexample must be read and evaluated by subscriber terminals using the RRCprotocol (Paging Type 1, System Information change Indication). Systeminformation which supposedly may be transmitted only rarely with analarm message will therefore be perceived without delay by the receivingsubscriber terminals.

By way of example, system information may be added as shown in theillustration in FIG. 2 a. By way of example, FIG. 2 a shows thestructure of a repeatedly transmitted frame FR with a multiplicity ofsystem information blocks SIB as well as a so-called master informationblock MIB, and two so-called scheduling blocks SCB 1 and SCB 2. Thesystem information blocks SIB 1 to SIB 18 which currently exist as shownin Table 8.1.1 in 3GPP TS 25.331, Rel. 6.4.0 have, for example, had anew system information block SIB 19 added to them. By way of example,“cell” would be assigned to this additional system information block asthe “area scope” in the table, in order to allow this to be transmittedon a radio-cell-specific basis. This is particularly worthwhile since,in general, alarm messages affect only a specific locally restrictedpart of the entire network.

In this case, the added system information block SIB 19 has a specificlength. If, for example, one byte (8 bits) is available as netinformation, then these 8 bits can be used to code N=255 differentso-called alarm category indicators which, for example, specifydifferent alarm causes such as fire, earthquake, flooding, etc., andthese are finally output as different alarm messages via the userinterface UI of the receiving subscriber terminal.

As an alternative to addition of the system information by one or moreadditional system information blocks, it is likewise feasible to useparts of one or more system information blocks which are normally usedfor other signalling purposes, for example as illustrated in FIG. 2 b.The presence of an alarm can be indicated by, for example, a specificcoding of alarm category indicators to those subscriber terminals whichnote a change in the content of the received system information with anappropriate reaction by them. By way of example, FIG. 2 b shows that thesystem information block SIB 3 has been coded with an alarm categoryindicator. The system information block SIB 3 which is specified inSection 8.1.1.6.3 of 3GPP TS 25.331, Rel. 6.4.0 is particularly suitablesince it is read by subscriber terminals both in the idling mode and inthe connected mode. Alternatively suitable system information blocks maybe chosen in the same manner for signalling of alarm categoryindicators.

The system information is added to or modified, for example, by thecontrolling radio network controller RNC for a number of radio cells,for example all of the radio cells or only a selection of the radiocells of the base stations NB which are linked via the radio networkcontroller. Depending on the alarm which the radio network controllerRNC receives, possibly via further devices in the system such as themobile switching center MSC or a gateway GW, from a central instance,for example a so-called alarm center AC in a public or private facility,the radio network controller RNC configures an appropriate systeminformation item and transmits this in the affected region from the basestations which cover this region. The alarm from the central instance inthis case relates, for example, to a specific definition of the alarmtype and of the radio cells and/or the geographic region in which thealarm is intended to be transmitted. The alarm signal is added to thesystem information by the radio network controller for a configurabletime interval, for example of several seconds, so that this does notresult in any long-term interference with active connections. This canadditionally be carried out more than once in order to ensure reliablereception by the receiving subscriber terminals.

According to 3GPP TS 25.331, Rel. 6.4., a subscriber terminal readssystem information which is transmitted on a broadcast channel BCH froma base station, both in the idle mode and the connected mode, in thefollowing states; CELL_FACH, CELL_PCH, URA_PCH and CELL_DCH. Inaddition, subscriber terminals which, in the FDD mode, supportsimultaneous reception of an SCCPCH (Secondary Common Control PhysicalChannel) and DPCH (Dedicated Physical Channel) receive, for example,system information on the FACH transport channel when they are in theso-called CELL_DCH state.

In a GSM-based system, the method can be implemented, particularly whenthe subscriber terminal is in the idle mode, in a largely correspondingmanner to the implementation in a UMTS-based system.

If the subscriber terminal is a device which supports onlycircuit-switched (CS) services, or no PBCCH (Packet Broadcast ControlChannel) is available in the radio channel, then the system informationon the broadcast channel BCCH is read. If, in contrast, the subscriberterminal supports packet-switched (PS) services and PBCCH is availablein the radio cell, then the subscriber terminal reads system informationon the PBCCH. In this context, reference should be made to Sections5.5.1.2 and 5.5.1.3 in 3GPP TS 44.060, Rel. 7.1.0.

For example, one byte of the “SI 4 Rest Octets” in the Type 4 systeminformation message may be used for alarm signaling and alarm categoryindication on the broadcast transmission channel BCCH. In this context,reference should be made to Section 10.5.2.35 in 3GPP TS 44.018, Rel.7.1.0. In a corresponding manner, if a PBCCH is available, alarmsignalling and alarm category indication can be coded within the packetsystem information. In this context, reference should be made toSections 11.2.18 to 11.2.25c in 3GPP TS 44.060, Rel. 7.1.0.

In the connected mode, that is to say during an active circuit-switchedconnection, or in the packet transfer mode, that is to say during activepacket data transmission, a system information message can betransmitted in a comparable manner on a dedicated or associated controlchannel. This can be done, for example, by transmitting one byte of the“SI 6 Rest Octets” in the Type 6 system information message, which istransmitted on the so-called SACCH (Slow Associated Control Channel).The “SI 6 Rest Octets” information element has a fixed length of 7bytes, of which only two or 3 are currently used, so that at least fourbytes are currently still available for further use. In the packettransfer mode, coding for alarm signaling and alarm category indicationshould be carried out within a system information message which istransmitted on the PACCH (Packet Associated Control Channel). In thiscontext, reference should once again be made to Sections 11.2.18 to11.2.25c in 3GPP TS 44.060, Rel. 7.1.0.

The method will be described once again in the following text on thebasis of the example of a flowchart as shown in FIG. 3, relating to thesystem configuration in FIG. 1 and the frame structure in FIG. 2. It isassumed that the base station is NB1 which is affected only indirectlyby the method periodically transmits signaling blocks SIB and furtherinformation blocks, in particular a master information block MIB using abroadcast channel on the radio interface, such that subscriber terminalsUE which are located in the radio cell Z1 of the base station NB1 canreceive this.

If an alarm message is now generated by a public or private so-calledalarm center AC, for example a fire-service control center, then, afterfurther processing which is not illustrated, implementation anddefinition of the geographical region within which this alarm message isintended to be transmitted, it is transmitted or signaled to the radionetwork controller RNC. The radio network controller in turn receivesthe alarm message Alarm and inserts a corresponding alarm categoryindicator Alarm into a system information block SIB. In this case, andin a corresponding manner to the description relating to FIGS. 2 a and 2b above, the alarm message may be added to, for example, by asupplementary specific system information block or by coding of a systeminformation block which is used for further signaling. If required, theradio network controller RNC uses the previously defined geographicregion for evaluation purposes before insertion of the alarm categoryindicator Alarm into the frame fr, to define which base station or whichbase stations should transmit the received alarm message, andappropriately adds to the frame fr of the selected base station or basestations.

Finally, the subscriber terminal UE which is located in the radio cellof the base station NB1 receives the alarm category indicator togetherwith further system information blocks, with this information beingevaluated by the subscriber terminal UE, and by access to alarm messageswhich are stored in a memory device SP in the subscriber terminal UE,converts this to an alarm message which can be understood by the user ofthe subscriber terminal UE, and outputs this, for example as an opticaland/or acoustic indication, via a user interface UI.

In addition to the methods described above, appropriate implementationsof the method in the relevant components and devices in a radiocommunications system are also included. For this purpose, these havebeen appropriately adapted for carrying out the method.

The system also includes permanent or removable storage, such asmagnetic and optical discs, RAM, ROM, etc. on which the process and datastructures of the present invention can be stored and distributed. Theprocesses can also be distributed via, for example, downloading over anetwork such as the Internet. The system can output the results to adisplay device, printer, readily accessible memory or another computeron a network.

A description has been provided with particular reference to preferredembodiments thereof and examples, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the claims which may include the phrase “at least one of A, B and C”as an alternative expression that means one or more of A, B and C may beused, contrary to the holding in Superguide v. DIRECTV, 358 F3d 870, 69USPQ2d 1865 (Fed. Cir. 2004).

What is claimed is:
 1. A method for emission of alarm messages tosubscriber terminals in a radio communications system, comprising:signaling presence of an alarm to the subscriber terminals by at leastone system information item from at least one base station in the radiocommunications system using a control channel; and transmitting at leastone respectively stored alarm message as a consequence of receiving theat least one system information item by the subscriber terminals.
 2. Themethod as claimed in claim 1, wherein the at least one respectivelystored alarm message is emitted at least one of optically andacoustically, by the subscriber terminals.
 3. The method as claimed inclaim 2, wherein the at least one system information item makes itpossible to distinguish between a plurality of alarm categories whichare emitted as corresponding alarm messages by the subscriber terminals.4. The method as claimed in claim 3, wherein the corresponding alarmmessages associated with the alarm categories are stored in thesubscriber terminals.
 5. The method as claimed in claim 4, wherein atleast one of the alarm categories is signaled to the subscriberterminals by at least one of an alarm system information item and codingof an informational system information item which contains otherinformation.
 6. A subscriber terminal for a radio communications systemhaving a base station, comprising: at least one receiving devicereceiving at least one system information item, transmitted by the basestation using a control channel, by which presence of an alarm issignaled; a memory device storing at least one alarm message; a controldevice controlling output of the at least one alarm message stored insaid memory device; and output means emitting the at least one alarmmessage.
 7. A radio network controller for a radio communicationssystem, comprising: at least one transmitting/receiving device receivingat least one alarm message and emitting the at least one alarm messageon a radio interface to at least one receiving subscriber terminal; anda control device controlling addition to at least one system informationitem about the at least one alarm message prior to transmission on theradio interface.
 8. A radio communications system, comprising: at leastone subscriber terminal; at least one radio network controller; and abase station signaling presence of an alarm to said at least onesubscriber terminal by at least one system information item using acontrol channel, said at least one subscriber terminal transmitting atleast one respectively stored alarm message as a consequence ofreceiving the at least one system information item.